Fuze



Dec. 30, 1969 J, J. GLQwAcKl 3,486,452

FUZE

N Filed May 6, 1954 Q x i 7 q) mw n\% u INVENTOR. Jahn J. Blnwack.

A TTDRNEYi United States Patent 3,486,452 FUZE John J. Glowacki,Plainville, Conn., assignor to the United States of America asrepresented by the Secretary of the Army Filed May 6, 1954, Ser. No.428,149

Int. Cl. F42c 11/02 U.S. Cl. 102-70.2 8 Claims This invention relates tofuzes for rotary projectiles and more particularly to fuzes for thedestruction of ammunition to which they are applied.

A primary object of my invention is to provide a simple fuze forprojectiles of the point detonating type which is very sensitive inoperation, yet is completely safe to handle.

Another object of my invention is to provide a fuzefor projectiles inwhich a detonator is exploded by energy from a piezoelectric crystal.

A further object of my invention is to provide a fuze having a pluralityof safety devices all resposive to the same force to arm the fuze.

Other objects will be in part apparent and in part pointed out in thefollowing specification.

The invention is carried out by the employment of a piezoelectriccrystal which is positioned to be mechanically struck when theprojectile engages a target. The output of the crystal is led through asuitable time delay mechanism to a detonator which is electricallyresponsive to explode a booster train to re the shell.

The invention accordingly comprises the elements and combinations ofelements and arrangement of parts hereinafter described and the scope ofthe invention is indicated in the appended claims.

I have shown a preferred embodiment of my invention in the accompanyingdrawing in which:

FIGURE l is a longitudinal elevation in section showing the internalarrangement of my invention.

FIGURE 2 is a cross section taken on lines 2--2 of FIGURE 1 and lookingin the direction of the arrows.

FIGURE 3 is a fragmentary elevation in section showing an enlargeddetail of the invention.

Referring now to FIGURE 1 there is shown at numeral 1 a tapered fuzebody, such body being of external ogive form and through which is formeda central axis opening. Starting more or less centrally the opening hasa shoulder 2 defining a portion of reduced diameter and serving toreceive an insulator 3 of general frusto-coni cal form and carrying apiezoelectric crystal 4 at the apex thereof. A conductor S runs from therear crystal terminal to an insulated binding post 6 on the fuze bodyThe other side of the crystal is adapted to be grounded when struck bythe impact assembly as will later be more fully explained. A wiper 13 isin electrical contact with the lead terminating at the binding post atone end thereof and engages a slip ring 14 adapted to be turned by aclock mechanism 15 at the other end. Since clOck mechanisms to delay thefiring of an explosive are well known, no attempt has been made toillustrate the details of the structure shown, however it will beunderstood that the slip ring 14 rotates at a predetermined rate andafter the expiration of a known time a connection is made to conductor15' which terminates in insulated block 16. A second conductor 17connects to electrically responsive detonator 18 at one end thereof andis in metallic engagement with conductor 15 at the insulator block. Aslidable metal plug 19 is normally in engagement with the exposedjunction between conductors 15 and 17, and as will be readily seen,connects such junction to the fuze body, or ground, and therebyeifectively short circuits the detonator, which goes to ground byconductor 20. A spring 21 31,486,452 Patented Dec. 30, 1969 urgesagainst detent plow 22 which has a beveled face bearing against a matingbeveled face on plug 19 substantially as shown. Y

A booster charge 23 is received rearwardly of the fuze and forms part ofthe explosive train to burst the pay load of the projectile. Interposedin cavity 24 leading between the detonator 18 and the booster charge 23is a normally closed gate assembly consisting of two interlocking pins25 slidable in radial ports and held in the closed position by detentmembers 26 and 27 which are urged rearwardly by compression springs 28and 29.

Disposed forward of the beforementioned shoulder 2 is a crystal impactassembly consisting of shaft 30 normally held with one end in spacedrelation with crystal 4 by pins 31 and 32 radially slidable inportsian'd held in position by detent members 33 and 34 which are, inturn, urged to rearward position by compression springs 3S and 36interposed between spider 37 and collar 38. The other end of shaft 30 isreceived within sleeve 39 and is pinned thereto for motion therewith byrivet 40. A second shaft 41 is slidably received in sleeve 39 and isnormally secured thereto by detent plugs 42 and 43 which are restrainedin the normal position by sleeve 44 slidably embracing sleeve 39 andmovable rearwardly under set back to be seized and held by resilientfingers 45.

A compression spring 46 resiliently urges between the respective ends ofthe several shafts for a purpose that will presently be explained. Aspring ring 47 is seated in a kerf formed in shaft 41 and rides forwardwhen the shaft is freed and moved by spring 46 to lock into kerf 48formed in sleeve 39. A bushing 50 is slidably fitted around the forwardpart of sleeve 39 and is provided with an outwardly flaring head 51 toseat against a step 53 formed in the fuse body. The bushing 50 isthreadedly fitted into a cap 52 which is adapted to be impacted againstand carried forward by motion of shaft 41 substantially as shown inFIGURE 3.

OPERATION When the projectile is discharged from the gun the set backforce moves sleeve 44 rearwardly to be seized and held by resilientfingers 45 as will be seen in FIGURE 3. The set back force also aids thecompression springs in forcing detent members 33, 34, 22, 26 and 27tightly against their several radially movable elements. When the setback force drops to zero, sleeve 44, normally holding plugs 42 and 43 inlocked position on shaft 41 (see FIGS. l and 2) moves rearwardly to freethem and then centrifugal force causes detent plugs 42 and 43 to yradially outward, and since shaft 41 is now free to move, compressionspring 46 forces it, together with bushing 50 and cap 52 to the forwardposition shown in FIGURE 3 wherein head 51 rests against step 53 andsplit ring 47 is seated in kerf 48. The impact assembly consisting ofshafts 30 and 41 and sleeve 39 are now locked together for motion as anentity. Simultaneously, centrifugal force moves pins 31 and 32 radiallyoutward in their ports and the assembly is free to move longitudinallyin the fuse body.

Slidable metal plug 19 moves outwardly thereby removing the shortcircuit from the detonator 18 and interlocking pins 25 are displacedoutwardly to open port 24 between the detonator and booster charge 23.

When the timing mechanism 15 has completed its cycle the fuze is fullyarmed and upon impact with a target, shaft 30 is driven rearwardlyimpacting against crystal 4 thereby at once imparting a mechanicalstress thereto and grounding the same, whereby electrical energy flowsthrough lead 5, contact 13, lead 15', lead 17, detonator 18 and lead 20to groundi and the detonator explodes. The flash from the detonatorpasses through port 24 to fire the booster charge and in turn theprojectile pay load.

I claim:

1. In a point detonating fuze for a rotatable projectile a body havingan axial passage from front to rear, an explosive train mounted thereinand comprising a detona-l tor explodable upon passage of electricalenergy therethrough, means to short circuit said detonator in fuzedisarmed position, a piezoelectric crystal in said passage, a circuit tosupply electrical energy to the said detonator and connected to saidcrystal, timing means forming a part of said circuit to close saidcircuit after a predetermined time interval, and means normally spacedfrom said crystal and adapted to impact against said crystal to groundthe same upon engagement of said fuze with a target.

2. In a point detonating fuze for a rotatable projectile a body havingan axial passage from front to rear, an explosive train mounted thereinand comprising a detonator explodable upon passage of electrical energytherethrough, means to short circuit said detonator in fuze dislarmedposition, said last mentioned means responsive to projectile spin toremove the short circuit to arm the fuze, a piezoelectric crystal insaid passage, a circuit connecting the said crystal with the saiddetonator, timing means forming a part of said circuit and adapted toclose the same after a predetermined interval, and means normally spacedfrom said crystal and adapted to impact thereagainst to ground the sameupon engagement of the said fuze with a target.

3. In a point detonating fuze for a rotatable projectile a body havingan axial passage from front to rear, an eX- plosive train mountedtherein and comprising a detonator explodable upon passage of electricalenergy therethrough, means t short circuit said detonator in fuzedisarmed position, said last mentioned means responsive to projectilespin to remove the short circuit to arm the fuze# `a piezoelectriccrystal in said passage, a circuit connecting said crystal with the'said detonator, timing means forming a part of said circuit and adaptedto close the same after a predetermined interval, means normally spacedfrom said crystal and adapted to impact thereagainst upon engagement ofthe said fuze with a target, and detent means arranged to engage thelast named means to maintain the same in lixed position in fuze disarmedcondition.

4. The invention according toclaim 3 wherein the said detent meanscomprises a plurality of pins seated in said normally spaced means andresponsive to centrifugal force to move radially in the said passage.

5. The invention according to claim 4 including a plurality of membersnormally interposed in said powder train to obstruct the same andresponsive to fuze spin to move radially in said passage.

6. In a point detonating fuze for a rotatable projectile a body havingan axial passage from front to rear, a detornator in said passage andexplodable upon passage therethrough of electrical energy, an explosivetrain formed in part at least by said detonator, means responsive tocentrifugal force to short circuit said detonator, a piezoelectriccrystal in said passage, a circuit connecting said crystal and saiddetonator, timing means forming a part of the said circuit, and animpact assembly in the front of said axial passage responsive to fuzeengagement with a target to strike and ground the said crystal, saidassembly comprising two pins longitudinally arranged in said passage, acompression spring between the said pins and a detent in the forward ofthe said two pins removable during fuze flight to permit the said springto urge the said forward pin outward beyond the front of said body.

7. In a fuze for use in a rotatable projectile having an axial passageextending from front to rear, a piezoelectric crystal, a detonator insaid passage and arranged to explode upon passage of electrical energytherethrough from said crystal and means to impact against said crystalcomprising a irst shaft disposed in spaced relation to said crystal, asecond shaft having a pair of axially spaced annular collars integral onits rearward portion aligned with said iirst shaft and spaced therefrom,a compression spring urging between said first and second shafts, a rstelongated sleeve extending at least between said irst and second shaftsand surrounding said compression spring, a plurality of detent pinspiercing said first sleeve and received in said second shaft, a secondsleeve embracing said first sleeve and said detent pins and movableunder the urging of set back force of said projectile to release saidpins from said second shaft, a kerf formed in said first sleeve adjacentan end of said second shaft, a spring ring normally seated between saidcollars and embracing said second shaft whereby upon cessation of saidset back force said compression spring forces said second shaft toextend beyond said fuze and engage said spring ring in said kerf in saidfirst sleeve whereby said tirst and second shafts and said lirst sleeveare locked for motion together.

8. In a point detonating fuze for a rotatable projectile a body havingan axial passage from front to rear, an explosive train comprising adetonator explodable upon the passage of electrical energy therethrough,means to short circuit said detonator said means responsive toprojectile rotation to remove said short circuit, a piezoelectriccrystal in said passage, a circuit to connect said crystal with saiddetonator, timing means forming a part of said circuit, means normallyspaced from said crystal adapted to impact thereagainst upon targetengagement and detent means received in said last named means tomaintain the said normal spacing in fuze disarmed condition.

References Cited UNITED STATES PATENTS 666,607 5/ 1929 France.

BENJAMIN A. BORCHELT, Primary Examiner US, Cl. X.R 102-73

1. IN A POINT DETONATING FUZE FOR A ROTATABLE PROJECTILE A BODY HAVINGAN AXIAL PASSAGE FROM FRONT TO REAR, AN EXPLOSIVE TRAIN MOUNTED THEREINAND COMPRISING A DETONATOR EXPLODABLE UPON PASSAGE OF ELECTRICAL ENERGYTHERETHROUGH, MEANS TO SHORT CIRCUIT SAID DETONATOR IN FUZE DISARMEDPOSITION, A PIEZOELECTRIC CRYSTAL IN SAID PASSAGE, A CIRCUIT TO SUPPLYELECTRICAL ENERGY TO THE SAID DETONATOR AND CONNECTED TO SAID CRYSTAL,TIMING MEANS FORMING A PART OF SAID CIRCUIT TO CLOSE SAID CIRCUIT AFTERA PREDETERMINED TIME INTERVAL, AND MEANS NORMALLY SPACED FROM SAIDCRYSTAL AND ADAPTED TO IMPACT AGAINST SAID CRYSTAL TO GROUND THE SAMEUPON ENGAGEMENT OF SAID FUZE WITH A TARGET.